Looking to shed some weight? Experts warn that too much HIIT training can do more harm than good

HIIT and Core class
Posted at 1:05 PM, Apr 05, 2021

Surveys have shown that many Americans gained weight during COVID-19 quarantines. But anyone trying to shed some pounds before the summer should be careful about how they do it.

High-intensity interval training, or HIIT workouts, are often appealing because they can be done in a short amount of time. The workouts involve short bursts of intense exercise, and a whole workout lasts about 10 minutes.

However, health experts say too much HIIT can actually be harmful to a person’s health.

"There's evidence that chronic high-intense exercise can cause structural as well as electrical damage to the heart," said Robert Mazzeo, a professor of integrative physiology at Colorado University-Boulder.

One study published by the American College of Sports Medicine compared HIIT training to moderate exercise. People who did HIIT routines three times a week for six weeks did not improve their blood pressure or body fat as much as those who did moderate workouts five days a week for the same amount of time.

“If your goal for exercise is health improvements and not athletic performance, you're not trying to improve your personal best time in any specific event. Moderate exercise produces these benefits, so you don't have to stress the body as much and with the HIIT,” Mazzeo said. “I believe the risks probably outweigh the benefits.”

After a long period of HIIT training, people may notice slipping performance in workouts, sleep disruptions and more frequent illness. Mazzeo says overworking the body can weaken its immune system and make a person more likely to get an infection.